1. Field of the Invention
The present invention relates to alternatively agitating and pumping liquid manure in a manure pit, and in particular, it relates to an improved agitating and pumping apparatus having a sliding gate valve which completely shuts off the flow of liquid manure out of the pit.
2. Description of the Prior Art
The storing of liquid manure in feed lot and dairy operations has become relatively common. The manure is allowed to flow to a pit wherein it is collected and stored until the operator or farmer is ready to dispose of the manure. For example, in a hog or dairy operation, the manure is stored in a pit during the winter months and is then removed from the pit and spread out on the fields prior to plowing.
The manure is substantially in a liquid form that contains solids that eventually settle out onto the bottom of the pit or float on top of the liquid. It is necessary first to agitate the liquid manure into a substantially uniform slurry before discharging the manure from the pit. In addition, the manure also contains other items and matter which have been carried into the manure pit which cause problems in discharging the manure. These items and other matter include straw from bedding, hay, twine, rags and even rubber gloves used to perform artificial insemination. Many of these items are not ground into small particles by the pump. Prior art agitating and discharge pumps have had operating problems when these other items have been taken in by the pump and discharged in only a partially-ground condition.
For example, in using prior art pumping apparatus that both agitates the liquid manure into a substantial slurry and discharges the slurried manure, the other items have clogged the valve that is used to close the discharge flow, resulting in the liquid manure leaking on the ground, causing a mess.
One example of a manure handling system is described in the Kellogg U.S. Pat. No. 3,367,583. The manure handling system includes a liquid storage tank for holding the liquid manure, a pump unit disposed near one side wall of the tank, and a rotatable hydraulic jet unit disposed centrally within the tank. The jet unit and the pump unit are connected by a transfer conduit which is fitted at both ends with quick detachable joints so that the unit can either connect the pump to the jet unit or the pump to a discharge tank and trailer unit. When the manure is being recirculated, the manure is required to flow up and out of the tank through conduit which can have obvious disadvantages in the wintertime.
The Vaughan U.S. Pat. No. 3,316,843 describes a tank sump pump having a discharge end which communicates with a vertically disposed conduit. A swinging-type flapper valve is positioned at an upper end of the conduit to determine whether the material being pumped is recirculated or flows through a discharge pipe to a suitable receptacle. A swinging-type flapper valve has the disadvantage that solid material can get wedged between the flapper portion of the valve and its seat. In addition, the sump pump includes a standard gate valve for permitting manure to be recirculated in the pit. The valve is actuated from an open to a closed position by a conventional screw mechanism. Again, solid material can get caught on the gate portion of the valve and on the valve seat such that the valve will not seat properly, letting material discharge into the tank instead of up through the vertical conduit.
The Wolford U.S. Pat. No. 4,145,008 describes a centrifugal pump for disintegrating solids contained in the waste material to convert solid or semi-solid waste material to a pumpable slurry. The pump of the Wolford Patent is not designed to recirculate the waste material within the tank.
The Erlitz U.S. Pat. No. 3,948,450 describes a liquid manure pump that swings the pump discharge pipe out of engagement with the pump so that the manure recirculates within the tank. The discharge pipe has a nipple which acts as a stop to aligh the discharge pipe for connection. If solid matter gets caught on the nipple, the discharge pipe will not be properly aligned.